This invention relates generally to a knife and sheath combination having a system for locking the knife in the sheath and for allowing unlocking of the knife from the sheath through use of a twisting motion being applied to the knife.
Fixed blade knives are typically provided with a sheath in order to both protect the blade during non-use of the knife, and also to prevent inadvertent injury which could result from the sharpened edge of the blade should the knife blade be exposed. Sheaths are typically constructed of leather or durable fabric, such as canvas or nylon, but may also be constructed of plastic or other materials. The most commonly known sheaths provide a receptacle for the blade and also a loop for allowing the sheath and knife to be carried by a user on his or her belt. The knife can typically be either inserted or withdrawn from the receptacle of the sheath with ease.
A problem with such sheaths is that the knife, if not locked to the sheath in some manner, can easily become disengaged from the sheath and fall out. While this may not present a problem in numerous applications where the sheath is carried in a substantially vertical configuration which allows the knife to reside in the sheath due to the force of gravity, there are circumstances where a sheath may encounter angular configurations other than vertical. For example, a rock climber wearing such a conventional sheath may cause the sheath to be presented in various angular configurations, including upside down. This could cause the knife to fall out of the sheath if some locking means is not provided. Another situation could be in underwater applications, such as for scuba divers. Because a diver could be in any number of positions, some sort of locking means needs to be provided for securely retaining the knife in the sheath. Of course, there are other examples where a locking knife and sheath would be desirable, such as in skydiving, for paratroopers, horseback riders, hunters, etc.
Various knife and sheath designs have been patented. For example, U.S. Pat. No. 5,146,684, issued to Hagler, discloses a sheath having an opening for receipt of a handle ridge provided a knife handle. U.S. Pat. No. 2,783,536, issued to McQueary, discloses a knife having a handle with a groove provided therein for receipt of a rib provided in the sheath.
U.S. Pat. No. 5,255,436, issued to Yoshida, discloses a sheath having a pivotal locking member for engaging a knife handle. U.S. Pat. No. 3,992,776, issued to Koppe, et al., discloses a sheath having a spring for engaging the blade of a knife.
U.S. Pat. Nos. 5,163,592 and 5,002,213, both issued to Newton, et al., disclose knife and sheath retention members, as does also U.S. Pat. No. 5,031,810, issued to Finn, et al.
French Patent Document No. 908,850 appears to disclose a spring member provided on a sheath for engaging with the handle and knife.
While the foregoing knife and sheath designs are known, there still exists a need for a knife and sheath which can be economically produced and which provide for an quick and easy locking and unlocking system.
In providing a locking arrangement for locking a knife in a sheath, it would be desirable to have a locking arrangement that could be operated by a user wearing thick gloves, such as that which may be worn by a scuba diver, climber, outdoorsman, or the like, and additionally, which could be actuated by a user having limited mobility in his or her hands or fingers, such as by someone having arthritis or injury. Such a locking arrangement would allow for easy insertion and positive locking of the knife in the sheath and would also allow for the knife to be readily withdrawn from the sheath.